Alert archive / Utah / Special Weather Statements in 2021
Special Weather Statement, NWS Salt Lake City, UT
NWS Salt Lake City, UT issued this special weather statement at Jul 23, 2021, 4:35 PM MDT for Cache County, Utah. It was in force for 25 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Jul 23, 2021, 4:35 PM MDT (22:35 UTC)
- Expired
- Jul 23, 2021, 5:00 PM MDT
- In force
- 25 min
- Issued by
- NWS Salt Lake City, UT
County Cache County, UT
The radar
The Salt Lake City radar (KMTX), 74 km from the middle of the area, began a volume at 22:36 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Salt Lake City I, UT (KSLC), launched 12:00Z, 10.6 hours before the alert went out and 115 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 64 J/kg
- Mixed-layer CIN
- -234 J/kg
- Mixed-layer LCL
- 1858 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 50 m²/s²
- 0-3 km storm-relative helicity
- 28 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
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</html>What forecasters said that day
The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Salt Lake City, UT wrote its last area forecast discussion before this special weather statement went out at Jul 23, 4:03 PM MDT, 32 minutes earlier.
Area forecast discussion, Jul 23, 4:03 PM MDT, 32 minutes before
Area Forecast Discussion National Weather Service Salt Lake City UT 403 PM MDT Fri Jul 23 2021 .SYNOPSIS...A dry westerly flow will spread over northern Utah through the weekend, while deep moisture will linger across the south leading to daily showers and thunderstorms with localized heavy rainfall. The ridge providing dry weather for northern Utah will move east by early next week which will open the door for moist southerly flow to move back across most of the forecast area. && .SHORT TERM (Through 12Z Monday)...Despite drier air moving in across northern Utah today, there remains enough low level moisture to generate some decent thunderstorms over the Raft River Range this afternoon producing strong winds and heavy rain. However, models are showing that subsidence near the 500mb level will become stronger and deeper later this afternoon and evening across northern Utah which should put a cap to thunderstorm development, so expecting any storms to die off fast early this evening. Drier air will continue to spread in across the remainder of northern Utah and Uinta County Wyoming tonight through Saturday, but the ridge will move east by Sunday pushing the subsidence portion of the ridge to our east and allow convection to once again develop over the Uintas by Sunday afternoon and evening. Moisture will be marginal at this time. Central Utah will dry a little more Saturday as the westerly to northwesterly flow penetrates this portion of the state, but the hiatus in thunderstorms will be short lived as convection will be on the increased Sunday over the central mountains. Light northerly flow over most of southern Utah combined with deep moisture will have thunderstorms capable of producing heavy rain to move down drainage exacerbating the potential for flash flooding. A flash flood watch remains in effect until midnight as storms over the higher terrain will drift southward this evening. St. George will have a good chance of having a cluster of thunderstorms move south southwest across them this evening as some high resolution models are in agreement on an instability bullseye over Washington County this evening. The northerly flow will continue through Saturday so the threat of flash flooding will continue, especially in the drainages that drain southward. By Sunday the ridge aloft will have moved east and the flow turns southeast importing moisture northward. Temperatures will average a few degrees above average in the north with temperatures averaging a few degrees below normal in the south due to clouds and thunderstorms. .LONG TERM (After 12Z Monday)...The low moving through New Mexico and Arizona over the weekend responsible for transitioning winds to more a of a northeasterly flow will exit to the west. That will allow for southerly flow to kick back in as the ridge centers to the east. Better moisture advection will build in from that direction, especially in northern Utah. Elsewhere, precipitable water values will stay similar from the remnant moisture associated with the aforementioned low along with more monsoonal moisture. Values around 1" or higher could build into central Utah. In northern Utah, values will likely surpass that mark Tuesday as conditions remain largely unchanged. Flash flooding will remain a threat. The storms will be similar to recent ones, aided by daytime heating and diminishing with loss of solar warming. Variations in the ridge position will influence PoPs each day in the forecast, but there's good confidence in the monsoonal set up remaining in place. The warmest temperatures of the week in southwest Wyoming and northern Utah are expected near the start, when the driest conditions are in place. Highs around 5F warmer than average are expected Monday, followed by slightly cooler, but still near average temperatures through Friday. Temperatures will mainly be around 5F cooler to near average in central and southern Utah. && .AVIATION... KSLC...VFR conditions are expected through the valid TAF period. Scattered mid and high clouds will decrease into the evening, but smoke will increase from the northwest. Visby is expected to remain above P6SM. Winds will switch to southeast around 04Z. Rest of Utah and southwest Wyoming...VFR conditions are expected through the valid TAF period. Isolated showers and thunderstorms will diminish in southwest Wyoming and northern Utah around 00Z. The chance for precipitation will last through 06Z in southern Utah, with heavy rain the main threat. A shower or thunderstorm over a TAF site could drop CIGs into MVFR range for a short amount of time. Smoke will increase in southwest Wyoming and northern Utah into Saturday, but visby is expected to remain above P6SM. && .FIRE WEATHER...The drier westerly flow has started to move in across the north today and will penetrate farther into central Utah this weekend, eliminating most thunderstorm activity in the north and reducing the threat of thunderstorms in the central area. Min RHs will fall below 15% in the north and some western valleys this weekend, but then trend upward as the flow switches to southerly by early next week importing more moisture and increasing chances of showers and thunderstorms. Deep moisture will remain over southern Utah, although it will be suppressed a little farther south Saturday than today, but then start spreading northward some Sunday and more so by Monday reaching fwx zone 492, and northeast into the Uintas. Widespread showers and thunderstorms are expected over the far southern fwx zones Saturday through Tuesday, while scattered showers and thunderstorms will be common just north of here on Saturday and into central Utah Sunday and Monday. RH values will remain elevated through the entire forecast period with min RH values in the 30-40% range with max RH values above 80% in many areas. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Flash Flood Watch until midnight MDT tonight for UTZ122>125-128. WY...None && SHORT TERM...Struthwolf LONG TERM...Wilson AVIATION...Wilson FIRE WEATHER...Struthwolf For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity For frequently asked questions about the Area Forecast Discussion visit... http://weather.gov/saltlakecity/general/afd_faqs.php
Hazardous weather outlook, Jul 23, 4:13 PM MDT, 22 minutes before
Hazardous Weather Outlook National Weather Service Salt Lake City UT 413 PM MDT Fri Jul 23 2021 UTZ101>131-WYZ021-250000- Great Salt Lake Desert and Mountains-Tooele and Rush Valleys- Eastern Box Elder County-Northern Wasatch Front-Salt Lake Valley- Utah Valley-Cache Valley/Utah Portion-Wasatch Back- Bear Lake and Bear River Valley-Wasatch Mountains I-80 North- Wasatch Mountains South of I-80-Western Uinta Mountains- Wasatch Plateau/Book Cliffs-Western Uinta Basin- Western Millard and Juab Counties-Eastern Juab/Millard Counties- Central Mountains-Sanpete Valley-Sevier Valley-Castle Country- San Rafael Swell-Southwest Utah-Lower Washington County- Zion National Park-Southern Mountains-Upper Sevier River Valleys- Bryce Canyon Country-South Central Utah- Capitol Reef National Park and Vicinity-Western Canyonlands- Glen Canyon Recreation Area/Lake Powell-Southwest Wyoming- 413 PM MDT Fri Jul 23 2021 This Hazardous Weather Outlook is for the western two thirds of Utah and southwest Wyoming. .DAY ONE...Tonight Showers and thunderstorms capable of producing heavy rain, gusty winds, and small hail will once again occur late this afternoon and evening. The strongest storms are expected across southern Utah where a potential for flash flooding exists, especially in prone areas such as slot canyons, burn scars, areas of steep terrain, and normally dry washes and streams. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Daily showers and thunderstorms capable of heavy rain, gusty winds and small hail will occur each afternoon and evening over mainly southern Utah Saturday and Sunday before spreading north again for the first half of the upcoming week. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed. Please relay any information about observed severe weather to the NWS while following all local, state, and CDC guidelines. For more information from NOAA/s National Weather Service visit... http://weather.gov/saltlakecity For information on potential road travel impacts visit... http://www.udottraffic.utah.gov/roadweatherforecast.aspx
In the hours before
Local storm report, Jul 23, 2:21 PM MDT, 2 hours 14 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
221 PM MDT FRI JUL 23 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0230 PM LIGHTNING SAINT GEORGE 37.11N 113.58W
07/22/2021 WASHINGTON UT NEWSPAPER
A LIGHTNING BOLT BLEW A FOUR FOOT WIDE HOLE
THROUGH THE ROOF OF A ST. GEORGE HOME,
STARTING A FIRE. NO ONE WAS HURT.
0706 PM TSTM WND DMG 1 ESE MIDVALE 40.61N 111.89W
07/22/2021 SALT LAKE UT PUBLIC
1-INCH TREE LIMBS BROKEN; SHINGLES BLOWN
OFF.
0715 PM TSTM WND DMG 1 N TAYLORSVILLE 40.68N 111.93W
07/22/2021 SALT LAKE UT PUBLIC
BROKEN TREE LIMBS CAUSED DAMAGE.
0715 PM HAIL 4 SSE SLC INTL ARPT 40.73N 111.95W
07/22/2021 M0.75 INCH SALT LAKE UT BROADCAST MEDIA
REPORTED FROM ABC 4 STUDIOS.
0715 PM TSTM WND DMG 1 N COTTONWOOD HEIGHTS 40.62N 111.81W
07/22/2021 SALT LAKE UT PUBLIC
A LARGE TREE HAS UPROOTED AND CRASHED INTO A
HOME, PLACING A HOLE IN THE ROOF. DAMAGE TO
AN AWNING IS ALSO NOTED. TIME ESTIMATED FROM
RADAR.
0730 PM TSTM WND DMG 1 N MURRAY 40.67N 111.89W
07/22/2021 SALT LAKE UT PUBLIC
POWER LINES BROKEN. MULTIPLE LARGE TREES
HAVE BEEN UPROOTED THROUGHOUT TOWN. REPORTS
OF CARPORT AND CAR DAMAGE, DAMAGE TO
BUSINESS SIGNS AND ROOFTOPS.
&&Special weather statement, Jul 23, 3:14 PM MDT, 1 hour 21 minutes before
Special Weather Statement National Weather Service Salt Lake City UT 314 PM MDT Fri Jul 23 2021 UTZ122-125-232200- Southwest Utah UT-Southern Mountains UT- 314 PM MDT Fri Jul 23 2021 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN IRON COUNTY UNTIL 400 PM MDT... At 314 PM MDT, National Weather Service Doppler radar indicated strong thunderstorms along a line extending from 19 miles northwest of Paragonah to 23 miles east of Eagle Valley...and moving east at 25 mph. Pea size hail and wind gusts of 40 to 55 mph will be possible. Locations impacted include... Lund. PRECAUTIONARY/PREPAREDNESS ACTIONS... If threatening weather approaches, take shelter in a sturdy building. To report severe weather, contact your nearest law enforcement agency. They will relay your report to the National Weather Service office in Salt Lake City. && LAT...LON 3806 11268 3782 11345 3799 11395 3814 11315 TIME...MOT...LOC 2114Z 274DEG 22KT 3810 11301 3795 11377 MT
Special weather statement, Jul 23, 3:27 PM MDT, 1 hour 8 minutes before
Special Weather Statement National Weather Service Salt Lake City UT 327 PM MDT Fri Jul 23 2021 UTZ101-232200- Great Salt Lake Desert and Mountains UT- 327 PM MDT Fri Jul 23 2021 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN BOX ELDER COUNTY UNTIL 400 PM MDT... At 326 PM MDT, National Weather Service Doppler radar indicated a strong thunderstorm near Park Valley, or 27 miles south of Malta... moving northeast at 25 mph. Penny to nickel size hail and wind gusts of 40 to 55 mph will be possible. Locations impacted include... Park Valley, Curlew Junction, Rosette and Standrod. This includes Utah Route 30 between mile markers 40 and 60, and between mile markers 69 and 77. PRECAUTIONARY/PREPAREDNESS ACTIONS... If threatening weather approaches, take shelter in a sturdy building. Heavy rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 4163 11346 4178 11361 4200 11341 4199 11298 TIME...MOT...LOC 2126Z 221DEG 22KT 4190 11333 MT
Special weather statement, Jul 23, 3:31 PM MDT, 1 hour 4 minutes before
Special Weather Statement National Weather Service Salt Lake City UT 331 PM MDT Fri Jul 23 2021 UTZ103-107-110-232200- Eastern Box Elder County UT-Wasatch Mountains I-80 North UT- Cache Valley/Utah Portion UT- 331 PM MDT Fri Jul 23 2021 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN CACHE AND NORTHEASTERN BOX ELDER COUNTIES UNTIL 400 PM MDT... At 331 PM MDT, National Weather Service Doppler radar indicated a strong thunderstorm near Plymouth, or 17 miles south of Malad... moving north at 5 mph. Pea size hail and wind gusts of 40 to 55 mph will be possible. Locations impacted include... Plymouth, Portage and Washakie. This includes Interstate 15 between mile markers 390 and 400. PRECAUTIONARY/PREPAREDNESS ACTIONS... If threatening weather approaches, take shelter in a sturdy building. Heavy rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 4184 11211 4188 11234 4200 11234 4200 11202 TIME...MOT...LOC 2131Z 192DEG 5KT 4194 11221 MT
Special weather statement, Jul 23, 4:04 PM MDT, 31 minutes before
Special Weather Statement National Weather Service Salt Lake City UT 404 PM MDT Fri Jul 23 2021 UTZ103-107-110-232230- Eastern Box Elder County UT-Wasatch Mountains I-80 North UT- Cache Valley/Utah Portion UT- 404 PM MDT Fri Jul 23 2021 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN CACHE AND NORTHEASTERN BOX ELDER COUNTIES UNTIL 430 PM MDT... At 404 PM MDT, National Weather Service Doppler radar indicated a strong thunderstorm over Plymouth, or 12 miles north of Tremonton... moving southeast at 10 mph. Penny to nickel size hail and wind gusts up to 50 mph will be possible. Locations impacted include... Tremonton, Cache, Smithfield, Clarkston, Trenton, Plymouth, Peter, Riverside, Benson, Garland, Honeyville, Elwood, Newton, Amalga, Fielding, Deweyville and Collinston. This includes Interstate 15 between mile markers 384 and 395. PRECAUTIONARY/PREPAREDNESS ACTIONS... If threatening weather approaches, take shelter in a sturdy building. Heavy rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 4184 11227 4198 11212 4186 11183 4165 11207 TIME...MOT...LOC 2204Z 309DEG 8KT 4187 11212 MT
Special weather statement, Jul 23, 4:35 PM MDT, 0 minutes before
Special Weather Statement National Weather Service Salt Lake City UT 435 PM MDT Fri Jul 23 2021 UTZ103-107-110-232300- Eastern Box Elder County UT-Wasatch Mountains I-80 North UT- Cache Valley/Utah Portion UT- 435 PM MDT Fri Jul 23 2021 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN CACHE AND EAST CENTRAL BOX ELDER COUNTIES UNTIL 500 PM MDT... At 434 PM MDT, National Weather Service Doppler radar indicated strong thunderstorms along a line extending from near Trenton to 6 miles northwest of Tremonton...and moving east at 10 mph. Pea size hail and wind gusts of 40 to 55 mph will be possible. Locations impacted include... Tremonton, Cache, Smithfield, Trenton, Peter, Riverside, Benson, Richmond, Garland, Elwood, Newton, Amalga, Fielding, Deweyville, Collinston, Bothwell and Thatcher. This includes the following highways... Interstate 15 between mile markers 376 and 386. Interstate 84 between mile markers 36 and 42. PRECAUTIONARY/PREPAREDNESS ACTIONS... If threatening weather approaches, take shelter in a sturdy building. Heavy rainfall is also occurring with these storms, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 4190 11165 4166 11213 4171 11240 4191 11192 TIME...MOT...LOC 2234Z 272DEG 7KT 4187 11193 4174 11224 MT
The office that day
Everything else NWS Salt Lake City, UT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 22, 6:01 PM MDT | Special Weather Statement | SLC | Tooele | 44 min |
| Jul 22, 6:47 PM MDT | Special Weather Statement | SLC | Utah | 43 min |
| Jul 22, 6:53 PM MDT | Areal Flood Advisory | SLC | Salt Lake | 112 min |
| Jul 22, 7:03 PM MDT | Special Weather Statement | SLC | Davis | 42 min |
| Jul 22, 7:07 PM MDT | Severe Thunderstorm Warning | SLC | Salt Lake, Utah | 23 min |
| Jul 22, 7:21 PM MDT | Severe Thunderstorm Warning | SLC | Davis, Morgan, Salt Lake, Summit | 24 min |
| Jul 22, 7:23 PM MDT | Flash Flood Warning | SLC | Utah | 82 min |
| Jul 22, 7:30 PM MDT | Special Weather Statement | SLC | Salt Lake | 30 min |
| Jul 22, 7:37 PM MDT | Areal Flood Advisory | SLC | Utah | 105 min |
| Jul 22, 7:44 PM MDT | Special Weather Statement | SLC | Salt Lake | 46 min |
| Jul 22, 7:52 PM MDT | Areal Flood Advisory | SLC | Salt Lake | 86 min |
| Jul 22, 8:01 PM MDT | Special Weather Statement | SLC | Morgan | 29 min |
| Jul 22, 8:11 PM MDT | Special Weather Statement | SLC | Davis | 49 min |
| Jul 22, 8:29 PM MDT | Severe Thunderstorm Warning | SLC | Davis, Salt Lake, Tooele | 31 min |
| Jul 22, 8:56 PM MDT | Special Weather Statement | SLC | Morgan, Salt Lake, Weber | 49 min |
| Jul 23, 3:20 AM MDT | Flash Flood Watch | SLC | Beaver, Garfield, Iron, Kane, Piute, Washington and 1 more | 21 hr |
| Jul 23, 2:34 PM MDT | Flash Flood Warning | SLC | Kane | 3 hr |
| Jul 23, 3:14 PM MDT | Special Weather Statement | SLC | Iron | 46 min |
| Jul 23, 3:27 PM MDT | Special Weather Statement | SLC | Box Elder | 33 min |
| Jul 23, 4:04 PM MDT | Special Weather Statement | SLC | Cache | 26 min |
| Jul 23, 5:03 PM MDT | Special Weather Statement | SLC | Cache | 27 min |
Nearby
Special Weather Statements in Utah, 2021Every special weather statement in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.